The present invention relates to magnetic signatures of structures such as naval ships, more particularly to physical modeling (e.g., for testing purposes) of such structures and of electronic systems utilizable for reducing their magnetic signatures.
Naval vessels are characterized by magnetic signatures that may be detectable by enemy devices. For instance, a ship's magnetic signature may render the ship susceptible to magnetic mines. Navies therefore implement various methods and systems for reducing magnetic signatures.
Conventional practice of magnetic signature reduction usually involves degaussing. Typical degaussing practice uses magnetometers, degaussing coils, and a computer (which executes a degaussing algorithm) to measure onboard magnetic fields and to estimate offboard magnetic fields. Basically, degaussing actively compensates for the induced and permanent magnetic signals of a ship.
Technical evaluation is usually required prior to deployment of a magnetic signature reduction system that is contemplated for a given ship. Such testing of the efficacy of a proposed magnetic signature reduction system may involve computer simulation and/or physical scale modeling. According to conventional design philosophy for a physical scale model (PSM) of a ship or other marine vessel, the structures and electronics of the PSM are artistically and laboriously fabricated with a view to matching the particular configurative details of the full-scale vessel and the magnetic signature reduction system being tested.
Construction of a conventional PSM can be difficult. In addition, once constructed, the conventional PSM does not lend itself to modification, since it essentially “seals up” the inner details within its outer skin; any design changes, corrections, or adjustments will thus require that the PSM be physically cut open, an expensive and time-consuming process.
The following references, each of which is incorporated herein by reference, are instructive on conventional practice of physical scale models: John J. Holmes, “Modeling a Ship's Ferromagnetic Signatures,” Synthesis Lectures on Computational Electromagnetics, 20 Jul. 2007; John J. Holmes, “Application of Models in the Design of Underwater Electromagnetic Signature Reduction Systems,” Naval Engineers Journal, Volume 119, Issue 4, pages 19-29, published online 22 Jan. 2008; S. Fry and C. E. Barthel, Jr., “Design and Construction of the Magnetic Model of the DE-52,” Naval Ordnance Laboratory, Washington, D.C., Technical Report NOLR 811, January 1947.